1. Field of the Invention
The present invention relates to artificial ground suitable for use in a golf course, ground unsuitable for cultivation and the like.
2. Description of Related Art
Heretofore, in a place such as a golf course where a large quantity of water is used for greens or fairways, water is intensively controlled. For example, Japanese Patent Unexamined Patent Publication Nos. 63-28331 and 1-120226 disclose a method in which a waterproof sheet is spread under the ground on which the green is planted and water penetrating through the green is collected by the sheet for re-utilization. In this manner, security and effective utilization of the water source is an important subject in the golf course.
On the other hand, there is a danger that scattering of agricultural chemicals for extermination of diseases and noxious insects will seriously contaminate the environment. Agricultural chemicals scattered onto a green in a golf course are caused to be mixed into a reservoir for city water together with rainwater, and the drinking water may be contaminated. Thus, contamination of the environment by agricultural chemicals is a large social problem and it is desired that the dispersion of agricultural chemicals be minimized.
However, since there are many plant diseases and noxious insects (cockroaches, ticks, nematodes and the like) which are media for viruses in a golf course using natural soil, extermination of diseases and noxious insects by agricultural chemicals is avoided and there is no guarantee that contamination of the environment can be suppressed completely. Further, the natural soil can not increase the amount of water collected, that is, the collection efficiency, because of the penetration by the water sufficiently and, accordingly, the practicality of water collection is lacking.